export const WebRtcStreamer = (function () {
  /**
   * Interface with WebRTC-streamer API
   * @constructor
   * @param {string} videoElement - id of the video element tag
   * @param {string} srvurl -  url of webrtc-streamer (default is current location)
   */
  let WebRtcStreamer = function WebRtcStreamer(videoElement, srvurl) {
    if (typeof videoElement === 'string') {
      this.videoElement = document.getElementById(videoElement);
    } else {
      this.videoElement = videoElement;
    }
    this.srvurl =
      srvurl ||
      location.protocol +
        '//' +
        window.location.hostname +
        ':' +
        window.location.port;
    this.pc = null;

    this.mediaConstraints = {
      offerToReceiveAudio: true,
      offerToReceiveVideo: true,
    };

    this.iceServers = null;
    this.earlyCandidates = [];
  };

  WebRtcStreamer.prototype._handleHttpErrors = function (response) {
    if (!response.ok) {
      throw Error(response.statusText);
    }
    return response;
  };

  /**
   * Connect a WebRTC Stream to videoElement
   * @param {string} videourl - id of WebRTC video stream
   * @param {string} audiourl - id of WebRTC audio stream
   * @param {string} options -  options of WebRTC call
   * @param {string} stream  -  local stream to send
   */
  WebRtcStreamer.prototype.connect = function (
    videourl,
    audiourl,
    options,
    localstream,
  ) {
    this.disconnect();

    // getIceServers is not already received
    if (!this.iceServers) {
      console.log('Get IceServers');

      fetch(this.srvurl + '/api/getIceServers')
        .then(this._handleHttpErrors)
        .then((response) => response.json())
        .then((response) =>
          this.onReceiveGetIceServers(
            response,
            videourl,
            audiourl,
            options,
            localstream,
          ),
        )
        .catch((error) => this.onError('getIceServers ' + error));
    } else {
      this.onReceiveGetIceServers(
        this.iceServers,
        videourl,
        audiourl,
        options,
        localstream,
      );
    }
  };

  /**
   * Disconnect a WebRTC Stream and clear videoElement source
   */
  WebRtcStreamer.prototype.disconnect = function () {
    if (this.videoElement?.srcObject) {
      this.videoElement.srcObject.getTracks().forEach((track) => {
        track.stop();
        this.videoElement.srcObject.removeTrack(track);
      });
    }
    if (this.pc) {
      fetch(this.srvurl + '/api/hangup?peerid=' + this.pc.peerid)
        .then(this._handleHttpErrors)
        .catch((error) => this.onError('hangup ' + error));

      try {
        this.pc.close();
      } catch (e) {
        console.log('Failure close peer connection:' + e);
      }
      this.pc = null;
    }
  };

  /*
   * GetIceServers callback
   */
  WebRtcStreamer.prototype.onReceiveGetIceServers = function (
    iceServers,
    videourl,
    audiourl,
    options,
    stream,
  ) {
    this.iceServers = iceServers;
    this.pcConfig = iceServers || { iceServers: [] };
    try {
      this.createPeerConnection();

      let callurl =
        this.srvurl +
        '/api/call?peerid=' +
        this.pc.peerid +
        '&url=' +
        encodeURIComponent(videourl);
      if (audiourl) {
        callurl += '&audiourl=' + encodeURIComponent(audiourl);
      }
      if (options) {
        callurl += '&options=' + encodeURIComponent(options);
      }

      if (stream) {
        this.pc.addStream(stream);
      }

      // clear early candidates
      this.earlyCandidates.length = 0;

      // create Offer
      this.pc.createOffer(this.mediaConstraints).then(
        (sessionDescription) => {
          console.log('Create offer:' + JSON.stringify(sessionDescription));

          this.pc.setLocalDescription(sessionDescription).then(
            () => {
              fetch(callurl, {
                method: 'POST',
                body: JSON.stringify(sessionDescription),
              })
                .then(this._handleHttpErrors)
                .then((response) => response.json())
                .catch((error) => this.onError('call ' + error))
                .then((response) => this.onReceiveCall(response))
                .catch((error) => this.onError('call ' + error));
            },
            (error) => {
              console.log('setLocalDescription error:' + JSON.stringify(error));
            },
          );
        },
        (error) => {
          alert('Create offer error:' + JSON.stringify(error));
        },
      );
    } catch (e) {
      this.disconnect();
      alert('connect error: ' + e);
    }
  };

  WebRtcStreamer.prototype.getIceCandidate = function () {
    fetch(this.srvurl + '/api/getIceCandidate?peerid=' + this.pc.peerid)
      .then(this._handleHttpErrors)
      .then((response) => response.json())
      .then((response) => this.onReceiveCandidate(response))
      .catch((error) => this.onError('getIceCandidate ' + error));
  };

  /*
   * create RTCPeerConnection
   */
  WebRtcStreamer.prototype.createPeerConnection = function () {
    console.log(
      'createPeerConnection  config: ' + JSON.stringify(this.pcConfig),
    );
    this.pc = new RTCPeerConnection(this.pcConfig);
    let pc = this.pc;
    pc.peerid = Math.random();

    pc.onicecandidate = (evt) => this.onIceCandidate(evt);
    pc.onaddstream = (evt) => this.onAddStream(evt);
    pc.oniceconnectionstatechange = (evt) => {
      console.log(
        'oniceconnectionstatechange  state: ' + pc.iceConnectionState,
      );
      if (this.videoElement) {
        if (pc.iceConnectionState === 'connected') {
          this.videoElement.style.opacity = '1.0';
        } else if (pc.iceConnectionState === 'disconnected') {
          this.videoElement.style.opacity = '0.25';
        } else if (
          pc.iceConnectionState === 'failed' ||
          pc.iceConnectionState === 'closed'
        ) {
          this.videoElement.style.opacity = '0.5';
        } else if (pc.iceConnectionState === 'new') {
          this.getIceCandidate();
        }
      }
    };
    pc.ondatachannel = function (evt) {
      console.log('remote datachannel created:' + JSON.stringify(evt));

      evt.channel.onopen = function () {
        console.log('remote datachannel open');
        this.send('remote channel openned');
      };
      evt.channel.onmessage = function (event) {
        console.log('remote datachannel recv:' + JSON.stringify(event.data));
      };
    };
    pc.onicegatheringstatechange = function () {
      if (pc.iceGatheringState === 'complete') {
        const recvs = pc.getReceivers();

        recvs.forEach((recv) => {
          if (recv.track && recv.track.kind === 'video') {
            console.log(
              'codecs:' + JSON.stringify(recv.getParameters().codecs),
            );
          }
        });
      }
    };

    try {
      let dataChannel = pc.createDataChannel('ClientDataChannel');
      dataChannel.onopen = function () {
        console.log('local datachannel open');
        this.send('local channel openned');
      };
      dataChannel.onmessage = function (evt) {
        console.log('local datachannel recv:' + JSON.stringify(evt.data));
      };
    } catch (e) {
      console.log('Cannor create datachannel error: ' + e);
    }

    console.log(
      'Created RTCPeerConnnection with config: ' +
        JSON.stringify(this.pcConfig),
    );
    return pc;
  };

  /*
   * RTCPeerConnection IceCandidate callback
   */
  WebRtcStreamer.prototype.onIceCandidate = function (event) {
    if (event.candidate) {
      if (this.pc.currentRemoteDescription) {
        this.addIceCandidate(this.pc.peerid, event.candidate);
      } else {
        this.earlyCandidates.push(event.candidate);
      }
    } else {
      console.log('End of candidates.');
    }
  };

  WebRtcStreamer.prototype.addIceCandidate = function (peerid, candidate) {
    fetch(this.srvurl + '/api/addIceCandidate?peerid=' + peerid, {
      method: 'POST',
      body: JSON.stringify(candidate),
    })
      .then(this._handleHttpErrors)
      .then((response) => response.json())
      .then((response) => {
        console.log('addIceCandidate ok:' + response);
      })
      .catch((error) => this.onError('addIceCandidate ' + error));
  };

  /*
   * RTCPeerConnection AddTrack callback
   */
  WebRtcStreamer.prototype.onAddStream = function (event) {
    console.log('Remote track added:' + JSON.stringify(event));

    this.videoElement.srcObject = event.stream;
    let promise = this.videoElement.play();
    if (promise !== undefined) {
      promise.catch((error) => {
        console.warn('error:' + error);
        this.videoElement.setAttribute('controls', true);
      });
    }
  };

  /*
   * AJAX /call callback
   */
  WebRtcStreamer.prototype.onReceiveCall = function (dataJson) {
    console.log('offer: ' + JSON.stringify(dataJson));
    let descr = new RTCSessionDescription(dataJson);
    this.pc.setRemoteDescription(descr).then(
      () => {
        console.log('setRemoteDescription ok');
        while (this.earlyCandidates.length) {
          let candidate = this.earlyCandidates.shift();
          this.addIceCandidate(this.pc.peerid, candidate);
        }

        this.getIceCandidate();
      },
      (error) => {
        console.log('setRemoteDescription error:' + JSON.stringify(error));
      },
    );
  };

  /*
   * AJAX /getIceCandidate callback
   */
  WebRtcStreamer.prototype.onReceiveCandidate = function (dataJson) {
    console.log('candidate: ' + JSON.stringify(dataJson));
    if (dataJson) {
      for (let i = 0; i < dataJson.length; i++) {
        let candidate = new RTCIceCandidate(dataJson[i]);

        console.log('Adding ICE candidate :' + JSON.stringify(candidate));
        this.pc.addIceCandidate(candidate).then(
          () => {
            console.log('addIceCandidate OK');
          },
          (error) => {
            console.log('addIceCandidate error:' + JSON.stringify(error));
          },
        );
      }
      this.pc.addIceCandidate();
    }
  };

  /*
   * AJAX callback for Error
   */
  WebRtcStreamer.prototype.onError = function (status) {
    console.log('onError:' + status);
  };

  return WebRtcStreamer;
})();

if (typeof window !== 'undefined' && typeof window.document !== 'undefined') {
  window.WebRtcStreamer = WebRtcStreamer;
}
if (typeof module !== 'undefined' && typeof module.exports !== 'undefined') {
  module.exports = WebRtcStreamer;
}
